1. Field of the Invention
The present invention relates generally to drug delivery devices, and more particularly to devices for storing, transporting and dissolving dry reagents.
2. Description of the Related Art
Medical treatments often involve solutions or suspensions of drugs or other reagents. Transporting and storing such solutions can be extremely expensive. Accordingly, it is advantageous to transport and store drugs or other reagents in a dry powdered or lyophilized form, reducing the bulk and weight, and to mix the reagents with a fluid just prior to administration.
U.S. Pat. No. 5,259,954 to Taylor, issued Nov. 9, 1993 (hereinafter xe2x80x9cthe ""954 patentxe2x80x9d) and U.S. Pat. No. 5,725,777, issued Mar. 10, 1998 (hereinafter xe2x80x9cthe ""777 patentxe2x80x9d) disclose a drug pack or xe2x80x9creagent modulexe2x80x9d suitable for storing dry reagents and for preparing solutions for administration by passing a fluid through the pack. Specifically, FIGS. 9-10 and 12-15 of the ""777 patent illustrate two embodiments in which a porous compression element constantly exerts an inward force on the dry reagent bed, keeping the reagents compacted even as the bed is eroded by passing fluid through the porous compression element and through the bed. This arrangement advantageously enables efficient, uniform dissolution of the reagent bed.
While the reagent modules of the ""954 and ""777 patents operate well in storing and dissolving reagent beds efficiently, there remains room for improvement. Specifically, automated assembly of the disclosed compression elements is difficult, tending to result in mis-orientation and tangling. Furthermore, the foam compression elements disclosed in the ""954 patent are difficult to disinfect and tend to retain any contaminants they are exposed to prior to assembly and during operation.
Accordingly, a need exists for improved drug delivery packs of the type disclosed in the ""954 and ""777 patents.
In satisfaction of this need, the present application provides a number of improvements over prior drug delivery packs. As the skilled artisan will readily appreciate from the disclosure herein, the improvements described herein can be employed in conjunction or independently of one another.
In accordance with one aspect of the present invention, an apparatus for delivering reagent in fluid form is provided. The apparatus includes a housing defining a fluid inlet and a fluid outlet, the housing including a slide mechanism movable between a first position and a second position. At least one dry reagent bed is housed within the housing. A compression component is positioned within the housing to compact the reagent bed in at least the second position. The slide mechanism engages and compresses the compression component in the second position, as compared to the first position.
In accordance with another aspect of the present invention, a method is provided for preparing a reagent delivery device for delivery of fluid form of reagent from dry form of the reagent. The method includes providing a reagent bed and a compression component enclosed within a housing. Subsequently the compression component is compacted to exert pressure on the reagent bed.
In accordance with another aspect of the present invention, a device is provided for delivering fluid form of a dry reagent housed therein. The device includes a housing that defines a fluid inlet and a fluid outlet. A dry reagent bed is housed within the housing and a compression component is positioned within the housing to exert pressure upon the dry reagent bed. The compression component includes a top end, a bottom end, and at least two spring elements that extend parallel along a spring axis between the top end and the bottom end.
In accordance with another aspect of the present invention, a spring is provided for reciprocation within a bore. The spring includes a top platform and a bottom platform, each with perforations for fluid flow therethrough. The spring additionally includes at least one spring column that extends between the top platform and the bottom platform. The spring column comprising a series of alternating loops along a spring axis.
In accordance with another aspect of the present invention, a reagent delivery device is provided. The device includes a dry reagent bed and a housing enclosing the dry reagent bed. The housing has a fluid inlet and a fluid outlet. A ratcheting mechanism allows at least two housing components to slide with respect to one another between a first locking position and a second locking position. In the first locking position, the housing defines a first fluid flow path between the inlet and the outlet, which path excludes the reagent bed. In the second locking position, the housing defines a second fluid flow path between the inlet and the outlet, which path includes the reagent bed.
In accordance with another aspect of the present invention, a method is provided for delivering a fluid form of a reagent from a dry form of the reagent within a housing. The method includes initially flowing a fluid through the housing but outside the reagent bed. A flow path is then altered to direct the fluid through the reagent bed.
In accordance with another aspect of the present invention, a method is provided for forming a device for delivering a fluid form of a reagent from a dried form of the reagent. The method includes lyophilizing an initial fluid form of the reagent within the device.